Para-dioxanones are used as a starting material in the manufacture of poly para-dioxanones. The poly para-dioxanones are used in the manufacture of adsorbable monofilament suture fibers and other adsorbable medical devices.
One method of preparing para-dioxanones is by oxidative dehydrogenation of dialkylene glycols. In U.S. Pat. Nos. 2,900,395 and 2,807,629, a copper chromite catalyst is used for the oxidation dehydrogenation of diethylene glycol. However, these patents report a yield of about 67-84% and a conversion of about 67-94%.
It has been found that the presence of impurities inhibit polymerization. Typical impurities in the preparation of 2-para-dioxanone include, unreacted dialkylene glycol and reaction by-products such as 2-para-dioxanol, para-dioxane, 2,3dihydro-para-dioxin (dioxene), alkylene glycol and carboxylic acids. Particularly, the production of carboxylic acids and hydroxylic compounds can hinder polymerization of 2-paradioxanones. Therefore, a process to produce a high purity paradioxanone ("polymerization grade") is desirable.
It is therefore an object of the present invention to provide a para-dioxanone preparation process with high conversion rate and selectivity.